The principal monuments of the Nezāri Ismaʿili state, which also defined and defended its boundaries, were the exceptionally well-constructed and provisioned castles that dominated the surrounding valleys and countryside. These castles varied in size from the massive fortified complex built on the sides and the top of a spur of the Alborz Mountains at Gerdkuh (q.v.) near Dāmḡān to a cluster of smaller independent fortified sites in Khorasan or the Anṣariya Djebel in Syria. Sometimes three or four large castles were built at a strategic site, such as Ferdows, to protect the southwest flank of the Ismaʿili state.

Although many of these castles in Persia were taken and demolished by the Mongols, the ruins still give an impression of their immense power. As far as we know there are no other Ismaʿili monuments still extant with the exception of isolated remains of pottery kilns, for instance at Andij in Alamut. It should be remembered that Ismaʿili castles, especially the larger ones, were used not only for defensive military purposes, but often constituted complete towns in themselves, acting as the seat of the local governor and his officials, and centers of learning and study, with extensive libraries built within the castle walls and containing valuable manuscripts and scientific instruments. They were also bases from which dāʾis (q.v.; the Ismaʿili missionaries) could be sent to other parts of the state.

From 483/1090, when Ḥasan-e Ṣabbāḥ gained control of the castle of Alamut, until 654/1256, when Rokn-al-Din Ḵoršāh surrendered to the Mongols, the Ismaʿili state consisted of four principal semi-autonomous areas—Rudbār in which Alamut and Lamasar were the principal fortresses, Qumes, the area around Dāmḡān and Semnān, which contained the formidable castles of Gerdkuh and Soru, and Qohestān, in the south of Khorasan, in which most of the recent discoveries of castles have been made. There were also additional sites in Ḵuzestān, Arrajān in particular, where the Ismaʿilis established their hegemony for a few years. The fourth important Ismaʿili area was in Syria where the Ismaʿilis were able to retain their independence until 671/1273, when the last of their castles surrendered to Baybars. The most important Syrian fortress was Maṣyāf, though the castle of Kahf was probably the main residence of the Ismaʿili leader, Rāšed al-Din Senān. This impressive stronghold remained a military post until Ottoman times and was destroyed only at the beginning of the nineteenth century. Another important Ismaʿili center was the cluster of castles around Qadmus including Ḵawābi, Roṣāfa, Qolayʿa, Maniqa and ʿOlleyqa.

In their attempts to persuade their fellow-citizens to join them in their fight against the Seljuqs, the Ismaʿilis often gained control of large fortresses that eventually had to be relinquished after a few years occupation. The outstanding example was their infiltration and occupation of the great castle of Šāhdiz overlooking the Seljuq capital of Isfahan, a considerable blow to the prestige of the Seljuqs. Almost at the same time, around 598/1100, the Ismaʿilis seized Ḵān Lanjān, only seventeen miles south of Isfahan and over 1,000 feet above the valley. Although the capture of Šāhdiz ended tragically, we must admire the verve and ingenuity of the Ismaʿilis.

From the very earliest days of its inception, the boundaries of the new Ismaʿili state had been firmly fixed and the main line of fortresses did not change during the next 166 years. From Alamut the line stretched east to Firuz Kuh and then along the road to Mašhad, past the great complex of strongholds between Semnān and Dāmḡān (q.v.). In Khorasan the line ran southward to Qohestān and the border with Sistān, and westward to Ferdows and Ṭabas. The Ismaʿilis well understood the need for quick communications between each of the centers and these were provided by means of smaller forts, watchtowers and beacons. The vital line of communication between Alamut and the Ismaʿili community in Syria was always kept open and there was regular interchange between these two centers.

The Ismaʿili fortresses are notable examples of military architecture. Their strategic position, and the skilled use of natural resources, ensured that despite the difficulties of the terrain the residents were well supplied with food and water and able to withstand a prolonged siege of many months, even years. Several major considerations were observed in the construction of Ismaʿili castles: The area chosen for fortification was in a strong and naturally defensive position, and in a terrain sufficiently remote and inaccessible to discourage attacks by their far more numerous Seljuq foe and other enemies. The complex of fortresses within the chosen area were able to support each other in the event of attack and possessed an efficient system of communication, whether by beacon or other means. The chosen area usually contained enough natural material, especially wood and stone, to allow for any construction or reconstruction to be carried out expeditiously and with the minimum labor force. The terrain was self-sufficient in water and food supplies—that is to say there was fertile ground and water near by.

The strategy was thus a defensive one and, in the mountains of Qohestān, Alamut, and in Syria, it worked admirably. It differed from that of the Crusaders, who built strong bases from which they pursued an offensive strategy. The Ismaʿilis were able to overcome, often in an astonishing way, the difficulty of building large fortresses on the rugged crest of a high mountain and solidly anchoring the fortress into the hard and unyielding rock. As precipitous an approach as possible was important as this avoided the need for extensive outer walls, and a steep angle of slope made it very difficult for an enemy to set up his ballistae or rely on conventional siege tactics such as sapping and mining. Of course, the Ismaʿilis took every precaution to block off any approach that lay in dead ground and so made their castles virtually impregnable.

Several of the castles were already in existence at the time of the Ismaʿili uprising in the early 480s/1090s and after declaring his allegiance to Ḥasan-e Ṣabbāḥ the new governor would set about rebuilding and enlarging his castle. This was an urgent matter as it was not long before Seljuq troops set out to defeat the “heretics.” The imminent task was to build underground storage rooms containing sufficient food for the garrison for several years. These were so well built that ʿAlāʾ-al-Din ʿAṭā Malek Jovayni, the historian of the Mongol era, complains bitterly how difficult it was to demolish the castle of Alamut after it had surrendered to the Mongols. He is clearly astonished at the amount of stores, both liquid and solid, the castle contained, all still in very good condition.

The military genius behind the construction of Is-maʿili castles seems to have been Bozorg-Omid, Ḥasan-e Ṣabbāḥ’s successor (518-32/1124-38). He rebuilt the castle of Lamasar, the largest Ismaʿili castle, with its complex and highly efficient water storage system. Wherever the slope of a fortified hill was large enough, a well-constructed water catchment area was constructed. When the present author located the site of Soru, not far from Dāmḡān, it was noted that in addition to the water catchment area, which needed to be defended by strong thick walls, water had also been channeled to the main castle from a smaller castle a mile away. The Ismaʿilis were skilled water engineers and agriculturists. Every Ismaʿili castle had a large number of deep limestone-lined water storage cisterns, which were roofed over. Steps led down to the water. Many of the valleys below the castles are now barren and infertile, but some still contain flourishing little farms. Soru is a prime example. In 1972, the present author and his team estimated that the castle of Lamasar was able to rely on almost 400,000 liters of water stored in the castle’s water cisterns and that supplementary water supplies could easily be obtained from the nearby Naina Rud. This amount would be sufficient to keep 500 men and 50 mules or horses in water for three months.

The Ismaʿili castles in Syria, apart from Kahf and Maṣyāf, were not built on the same massive scale as those in Persia. It was some time before the Ismaʿilis were able to acquire their own castles (524-34/1130-40) and often there was insufficient space available to enlarge them greatly, although the walls, entrances and outworks were often rebuilt or strengthened considerably. Thus the Syrian castles tended to be more compact, although they were well provisioned and able to withstand a prolonged siege. The castle of Ḵawābi, for instance, was never taken by Crusaders and the site was reoccupied at the beginning of the 20th century by Syrians who continue to live in the castle ruins. An epigraph shows the date of 708/1308.

Kahf and Maṣyāf are the two most interesting castles in the area. Kahf was the headquarters of Rāšed-al-Din Senān and the last Ismaʿili stronghold to submit to Baybars. It is set on a rocky hill, almost completely covered by undergrowth, overlooking a deep valley and is over 600 meters long. The most important building still standing is the ḥammām or bathhouse, a large and exceptionally well proportioned and elaborate complex, hewn from solid rock on the south side of the castle. Water was brought from a spring 2 kilometers away. Three gates lead into the castle, again hewn from the rock, on which are carved important inscriptions and Qurʾanic verses.

Maṣyāf is the best preserved of the Ismaʿili castles in Syria. It had its origins in Seleucid, Roman and Byzantine eras, and was acquired by the Ismaʿilis in 535/1140 and together with Kahf became the center of Ismaʿili power. It was, however, more exposed than Kahf, besieged unsuccessfully by Saladin in 571/1176, and eventually surrendered to Baybars. The castle was surveyed by Michael Braune in 1983-84 in conjunction with the German Archaeological Institute in Syria and he has compiled a list of thirteen epigraphs in Maṣyāf, most of them dating from 646-47/1248-49, although there is an earlier one of 621/1224. The latest was 1191/1777. Such epigraphs are not found in Persian Ismaʿili castles, but are fairly common in Syria. The defensive arrangements of Maṣyāf are very impressive, and include extensive use of the bent entrance and the concentric principle of fortification.

When the Mongols under Hulagu Khan invaded the Alamut Valley in November 654/1256, they wisely made for the weakest Ismaʿili castle from the military point of view, Maymun Dez. The castle was not set on a great ridge like Alamut and the Mongols were able to use their mangonels with devastating effect. The Ismaʿili Imam, Rokn-al-Din Ḵoršāh, like most other rulers, stood in awe of the Mongols, and soon agreed to surrender all his castles to them. Some of his garrison commanders were reluctant to follow and Lamasar did not surrender for a year. Gerdkuh held out for 17 years. It would have been interesting to see what the outcome would have been if the Ismaʿilis had been able to offer a more spirited resistance. Many of the castles could have withstood a prolonged siege without much difficulty.

The present author has identified the location of a large number of Ismaʿili castles in the last decades of the 20th century, thus making it possible to appreciate more fully the power and influence of the Ismaʿili state, especially the part played by Qohestān. The fortresses at Qāʾen, Fourk, and Šāhdiz are particularly impressive. The ruins of Moʾmenābād cover a large area and this must have been a particularly impressive fortress and city. It was not far from the borders of Qohestān and because of its importance needed to be strongly protected. The Mongols set about its destruction with ferocity. The main curtain wall stretched for about 2 miles over sandy dunes. The track leading to it was closed in 1997 and declared impassable.



Max Van Berchem, “Épigraphie des Assassins du Syrie,” JA, série, 9, 1897, pp. 453-501; repr. in idem, Opera Minora, Geneva, 1978, vol. I, pp. 453-501.

Michael Braune, Untersuchungen zur mittelalterlichen Befestigung in Nordwest-Syrien: Die Assassinenburg Masyāf, Damascus, 1985. Bernard Hourcade, Alamut, EIr., I, pp. 797-801.

Wladimir Ivanow, Alamut and Lamasar: Two Mediaeval Ismaili Strongholds in Iran, Tehran, 1960.

ʿAlāʾ-al-Din ʿAṭā Malek Jovayni, Tāriḵ-e jahāngošā, tr. John Andrew Boyle as The History of the World-Conqueror, 2 vols., Manchester, 1958.

M. Kervran, “Une Forteresse d’Azerbaidjan: Samirān,” REI 41, 1973, pp. 71-93.

Caro O. Minasian, Shah Diz of Ismaʿili Fame, Its Siege and Destruction, London, 1971.

J. Phillips, “Assassin Castles in Syria,” The Connoisseur, No. 770, 1976, pp. 287-89.

Samuel M. Stern, with E. Beazley, and A. Dobson, “The Fortress of Khān Lanjān,” Iran 9, 1971, pp. 49-57.

Manučehr Sotuda, Qelāʿ-e Esmāʿiliya, Tehran, 1966. Peter Willey, The Castles of the Assassins, London, 1963.

Idem, “The Valley of the Assassins,” Royal Central Asian Journal 48, 1961, pp. 147-51.

Idem, “Further Expeditions to the Valleys of the Assassins,” Royal Central Asian Journal 54, 1967, pp. 156-62.

Idem, “The Assassins in Quhistan,” Royal Central Asian Journal 55, 1968, pp. 180-83.

Idem, “The 1972 Assassin Expedition,” Royal Central Asian Journal 61, 1974, pp. 60-70.

Idem, University Lectures in Islamic Studies, Vol. II, Altajir World of Islam Trust, 1998, pp. 167-81.

Idem, The Eagle’s Nest: Ismaili Castles in Iran and Syria, London, 2004.

(Peter Willey)

Originally Published: December 15, 2007

Last Updated: April 5, 2012

This article is available in print.
Vol. XIV, Fasc. 2, pp 205-208